Creutzfeldt-Jakob disease

Definition

Creutzfeldt-Jakob disease (CJD) is a form of brain damage that leads to a rapid decrease of mental function and movement.

Alternative Names

Transmissible spongiform encephalopathy; vCJD; CJD; Jacob-Creutzfeldt disease

Causes

CJD is believed to result from a protein called a prion. A prion causes normal proteins to fold abnormally. This affects the other proteins' ability to function.

There are several types of CJD. The disorder is very rare, occurring in about 1 out of 1 million people. It usually first appears between ages 20 and 70, with average age at onset of symptoms in the late 50s.

CJD can be grouped into classic or new variant disease.

The classic types of CJD are:

  • Sporadic CJD makes up the majority of cases. It occurs for no known reason. Average age at onset is 65
  • Familial CJD results when a person inherited the abnormal prion (inherited CJD is rare)

Classic CJD is not related to mad cow disease (bovine spongiform encephalitis).

However, new variant CJD (nvCJD) is an infectious form that is related to mad cow disease. The infection responsible for the disease in cows is believed to be the same one responsible for vCJD in humans.

New variant CJD accounts for less than 1% of cases, and tends to affect younger people. It can result when someone is exposed to contaminated products. Other nvCJD cases have occurred when people were given corneal transplants from infected donors, and from contaminated electrodes that were used in brain surgery (before it was known how to properly disinfect instruments).

There have not been any cases of nvCJD reported in the U.S.

CJD may be related to several other diseases also thought to be caused by prions, including kuru (seen in New Guinea women who ate the brains of deceased relatives as part of a funerary ritual), scrapie (found in sheep), chronic wasting disease (found in deer), and other rare human diseases, such as Gerstmann-Straussler-Scheinker disease and fatal familial insomnia.

Symptoms

CJD is rarely confused with other types of dementia (such as Alzheimer's disease) because in CJD, symptoms progress much more rapidly. Both forms of CJD are distinguished by extremely rapid progression from onset of symptoms to disability and death.

Exams and Tests

Early in the disease, a neurological and mental status examination will show memory problems and changes in other mental functions. Later in the course of the disease, a motor system examination will show muscle twitching and spasm, a strong startle response, and an increase in muscle tone. There may also be weakness and loss of mucle tissue (muscle wasting) and abnormal reflexes or increased normal reflex responses.

There is loss of coordination related to visual-spatial perception changes and changes in the cerebellum, the area of the brain that controls coordination (cerebellar ataxia). An eye examination shows areas of blindness that the person may not realize are present.

Tests used to diagnose this condition may include:

  • Brain MRI
  • EEG
  • Spinal tap
  • Blood tests to rule out other forms of dementia and to look for markers that sometimes accompany the disease

Ultimately, the disease can only be confirmed by brain biopsy or autopsy.

Treatment

There is no known cure. Interleukins and other medications may be use in an attempt to slow the progression of the disease. Custodial care may be required early in the course of the disease. Medications may be needed to control aggressive behaviors.

Provding a safe environment, controlling aggressive or agitated behavior, and meeting physiologic needs may require monitoring and assistance in the home or in an institutionalized setting. Family counseling may help in coping with the changes required for home care.

Visiting nurses or aides, volunteer services, homemakers, adult protective services, and other community resources may be helpful in caring for the person with CJD.

As with other illnesses that cause dementia, behavior modification may be helpful, in some cases, for controlling unacceptable or dangerous behaviors. This consists of rewarding appropriate or positive behaviors and ignoring inappropriate behaviors (within the bounds of safety). Reality orientation, with repeated reinforcement of environmental and other cues, may help reduce disorientation.

Legal advice may be appropriate early in the course of the disorder to form advance directives, power of attorney, and other legal actions that may make it easier to make ethical decisions regarding the care of an individual with CJD.

Outlook (Prognosis)

The outcome is usually very poor. Within 6 months or less of the onset of symptoms, the person will become incapable of self-care.

The disorder is fatal in a short time, usually within 8 months, but a few people survive as long as 1 or 2 years after diagnosis. The cause of death is usually infection, heart failure, or respiratory failure.

Possible Complications

  • Infection
  • Heart failure
  • Respiratory failure
  • Loss of ability to function or care for oneself
  • Loss of ability to interact with others
  • Death

When to Contact a Medical Professional

CJD is not a medical emergency, but early diagnosis and treatment may make the symptoms easier to control, allow patients time to make advance directives, and give families additional time to come to terms with the condition.

Prevention

Medical equipment is sterilized to kill organisms that may cause the disease. Persons who have a medical history of diagnosed or possible CJD are not used as cornea donors.

Most countries now have strict guidelines for management of infected cows and strict restrictions regarding what they are fed, to avoid the potential for transmission of CJD to humans.

References

Zeidler M. Prion diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 442.


Review Date: 8/29/2009
Reviewed By: Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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